Utility-Belt

This is my Rust library of potentially useful tools for Advent of Code.

Using

Add utility-belt to your Cargo.toml:

[dependencies]
utility-belt = { git = "https://github.com/DataWraith/utility-belt.git" }

In your Advent of Code projects, simply use utility_belt::prelude::*;.

What's currently here?

Re-exports

Most of the heavy-lifting is done by the other libraries this crate re-exports:

• ahash - fast HashMap and HashSet implementation
• bittle - zero-cost bitsets over native Rust types
• counter - count elements in iterables
• indoc - exposes macros for convenient inline String formatting
• itertools - various tools for working with iterators
• ndarray - n-dimensional container for general elements

Advent of Code-specific tools

• Grid2D, a convenient 2D grid backed by ndarray::Array2. It comes with the ability to parse grids from the usual puzzle-input format for grids and provides various utility functions for working with 2D grids.

  Comes with various ancillary structs (e.g. Direction and Coordinate) to make working with grids easier.

• A few useful math functions (gcd and lcm for now), a few helpers for working with polynomials.

• Functions for calculating area of a simple polygon and determining whether or not a point is inside of a polygon.

• Cumulative sum helpers in 1D (PrefixSum) and 2D (SummedAreaTable).

  These allow you to quickly look up the sum of values in a given 1D range or 2D rectangle.

• bisection search function

• union-find datastructure for easy connected components analysis

• path contraction for iterating a function millions of times, provided that there are cycles in the state-space path the function induces.

• state iteration

  The idea is to have a HashMap containing the current states. Then a transition function is applied to each state, and the resulting state(s) are collected into a new HashMap.

  The HashMap keeps track of how often a given state has occurred. This can be used to, for example, count how often a state is visited in a finite state machine after n iterations.

• an implementation of branch and bound

• Small bitsets for 8, 16, 32, 64 and 128 values

• Beam Search

• Solving equation systems using Gauss-Jordan elimination

• Chinese Remainder Theorem